showing a popup only if the logged user is not present on a sharepoint list

[antonioam]

Hi, when my app opens, i need to show to my user a sort of disclaimer, basically a popup that needs to appear only if the logged in user is not present on a sharepoint list. So if someone open the app and is present on the sharepoint, he should use the app normally, if he is not present on the list, he should see this popup, he should then click ok button and the popup should disapper, allowing him to use the app.

For doing this i followed 3 steps

1. I created my popup, a group of elements (rectangle, label and button) and gave its visible property a variable "disclaimer".
2. I made a simple updateContext({disclaimer: false}) on the onClick property of the button
3. I wrote the following code inside my OnVisible property of the app screen 

Set(
    disclaimer,
    If(
        IsBlank(
            First(
                Filter(
                    mySharepointList,
                    User().Email = User.Email
                )
            ).Email
        ),
        true,
        false
    )
)

something doesn't work... my disclaimer variable is always false. 
what am i doing wrong? seems like it's not evaluating the onVisible property

edit: 

i created a test variable that i set to 

IsBlank(First(
    Filter(
    mySharepointList,
    User().Email = User.Email
)
).Email)

and it shows me the correct value. but at the same time, the disclaimer variable which is basically set to the same, just with a Set property inside the screen onVisible, is always set to false!!!! so it's definitely like it won't run the set inside the onVisible, but how to fix? i could place the function directly inside the Visible field of the group but then i won't be able to remove the group visibility if the user press the button. how can i fix? 

[WarrenBelz · Accepted solution]

HI @antonioam ,

Your major issue here is that your Set (Global) Variable (which you can shorten to this)

Set(
   disclaimer(
      IsBlank(
         LookUp(
            mySharepointList,
            User.Email = User().Email
         )
      )
   )
)

is a completely different Variable to your UpdateContext Variable

UpdateContext({disclaimer: false})

(which also takes precedent on the screen), so either leave the whole thing as Global if you need to access it across different screens or set it on the screen you need with

UpdateContext(
   {
      disclaimer:
      IsBlank(
         LookUp(
            mySharepointList,
            User.Email = User().Email
         )
      )
   }
)

I am also assuming here User is a Person column in your list.

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[antonioam]

Hi, i remembered that a variable always gets set with Set and then is changed with Update context but from what you are saying i get that Set is used to instantiate and change global variables while updatecontext is used to instantiate and change temp variable, did i understand correctly?

still i tried to use your code but the disclaimer variable always stays on false, what can be the issue? can the problem be that the screen is the first one, so it doesn't get correctly the onVisible event?

[WarrenBelz]

Hi @antonioam .

They are two completely different Variables - even though they have the same name. UpdateContext() sets a Variable that exists only on the screen you set it on. Set() sets a "Global" Variable that exists across all screens. If both have the same name (a bad practice - I use gbl for Global Variables and var for Context), and you refer to the name on the screen the Context Variable exists, it does not matter what you do with the Global Variable, Power Apps will take the value of the Context Variable, so the best practice is simply not to name them the same. You also need to set the Context Variable on the screen you want to use it on (you can actually have several Context Variables with the same name on different screens and each will have the value you set on that screen). MS Reference doc is here.

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[antonioam]

hello, thanks for the explaination. what do you think it can be the issue in my case?

i changed as you suggested, using a context variable, but it still won't work. 

The variable never goes on false, seems like the onVisible code is not evaluated... 

[WarrenBelz]

@antonioam ,

I assume you are setting the Context Variable on the same screen as the item with the Visible property relying on it ? If you do this at screen OnVisible

UpdateContext(
   {
      disclaimer:
      IsBlank(
         LookUp(
            mySharepointList,
            User.Email = User().Email
         ).ID
      )
   }
)

 Assuming you want the item to be Visible when this is true, your Visible property would be

disclaimer

Also get rid of the Set Variable as this will only cause confusion.

Please click Accept as solution if my post helped you solve your issue. This will help others find it more readily. It also closes the item. If the content was useful in other ways, please consider giving it Thumbs Up.

MVP (Business Applications)   Visit my blog Practical Power Apps